Ex Situ Fabrication of Polypyrrole-Coated Core-Shell Nanoparticles for High-Performance Coin Cell Supercapacitor.

Silica-conducting polymer (SiO₂-CP) has the advantages of high electrical conductivity, structural stability, and the facile formation of thin-film. This work deals with the preparation and optimization of polypyrrole (PPy)-encapsulated silica nanoparticles (SiO₂ NPs) using an ex situ method. The SiO₂-PPy core-shell NPs prepared by the ex situ method are well dispersed in water and facilitate the mass production of thin-film electrodes with improved electrical and electrochemical performances using a simple solution process. As-prepared SiO₂-PPy core-shell NPs with different particle sizes were applied to electrode materials for two-electrode supercapacitors based on coin cell batteries. It was confirmed that the areal capacitance (73.1 mF/cm²), volumetric capacitance (243.5 F/cm³), and cycling stability (88.9% after 5000 cycles) of the coin cell employing the ex situ core-shell was superior to that of the conventional core-shell (4.2 mF/cm², 14.2 mF/cm³, and 82.2%). Considering these facts, the ex situ method provides a facile way to produce highly-conductive thin-film electrodes with enhanced electrical and electrochemical properties for the coin cell supercapacitor application.